The Compute's Gazette Disk menu used raster tricks to set the background color on a per-line basis, and the Demon Attack cartridge used a black character color as the "apparent" background while it changed the background color every scan line to achieve colorful demons like the Atari 2600 version. My recollection is that the Compute's Gazette menu did not use interrupts (it simply busy-waited for a keystroke) but I'm not sure about Demon Attack. There are some other cartridges from that era that used raster tricks, but I didn't have them back in the day and I'm not sure about the particulars.
If one did want to use interrupts, one would need to make use of the timers on the VIA. The easiest way to exploit them would probably be to figure some number of regularly-spaced intervals near where an interrupt would be useful, set the timer to go off that often, and either busy-wait for the scan line one was interested in, or else return if it wouldn't come around until after the next interrupt. Not a terribly efficient approach, but one that might still be better than simply busy-waiting all the time.
If I ever port Toyshop Trouble to the VIC-20, it will make use of raster timing to set the background color register four times per scan line as toys move left and right. With proper timing, it should be possible to cut the size of the "conflict zone" when a player is near a toy from 8 pixels wide to 4 pixels (I think writes to $900F can occur on arbitrary 4-pixel boundaries). Making that work, however, would require busy-waiting for much of the display period, since a normal "CMP/BNE" loop would have six cycles worth of slop, and I don't know of any way to clean that up without burning two more scan lines.